阅读说明：本技术 一种偏置电场下重离子辐射碳化硅二极管的损伤分析方法 (Damage analysis method for heavy ion radiation silicon carbide diode under bias electric field ) 是由 郭红霞 张鸿 潘霄宇 周益春 张凤祁 张晋新 琚安安 钟向丽 廖敏 于 2020-04-21 设计创作，主要内容包括：一种偏置电场下重离子辐射碳化硅二极管的损伤分析方法,包括：基于碳化硅二极管的基本结构和材料组成,通过Geant4构建碳化硅二极管的仿真模型,并在Geant4中设定偏置电场的大小和入射粒子的种类、能量；在Geant4中进行仿真模拟：将入射粒子射入碳化硅二极管,模拟不同偏置电场下入射粒子在碳化硅二极管内的粒子运动轨迹及碳化硅二极管的初始缺陷损伤分布；基于仿真模型和初始缺陷损伤分布,通过TCAD软件模拟碳化硅二极管的缺陷损伤演化过程,以分析缺陷损伤对碳化硅二极管的电学性能的影响。揭示偏置电场与辐射损伤的相互作用关系,对碳化硅器件的辐射效应机理分析和可靠性评估提供了技术基础。(A damage analysis method of a heavy ion radiation silicon carbide diode under a bias electric field comprises the following steps: based on the basic structure and material composition of the silicon carbide diode, a simulation model of the silicon carbide diode is constructed through Geant4, and the magnitude of a bias electric field and the type and energy of incident particles are set in Geant 4; simulation was performed in Geant 4: injecting incident particles into the silicon carbide diode, and simulating particle motion tracks of the incident particles in the silicon carbide diode under different bias electric fields and initial defect damage distribution of the silicon carbide diode; based on the simulation model and the initial defect damage distribution, the defect damage evolution process of the silicon carbide diode is simulated through TCAD software so as to analyze the influence of the defect damage on the electrical performance of the silicon carbide diode. The interaction relation between the bias electric field and the radiation damage is disclosed, and a technical basis is provided for the radiation effect mechanism analysis and the reliability evaluation of the silicon carbide device.)

1. A method for analyzing damage of a heavy ion radiation silicon carbide diode under a bias electric field is characterized by comprising the following steps:

constructing a simulation model of the silicon carbide diode through Geant4 based on the basic structure and material composition of the silicon carbide diode;

simulation was performed in Geant4, including: injecting incident particles into the silicon carbide diode, and simulating particle motion tracks of the incident particles in the silicon carbide diode under different bias electric fields and initial defect damage distribution of the silicon carbide diode;

and simulating the defect damage evolution process of the silicon carbide diode through TCAD software based on the simulation model and the initial defect damage distribution of the silicon carbide diode so as to analyze the influence of the defect damage on the electrical performance of the silicon carbide diode.

2. The method of claim 1, wherein prior to constructing the simulation model of the silicon carbide diode, further comprising:

and utilizing FIB (Focused Ion beam) to longitudinally cut the silicon carbide diode, and calibrating the components of each layer of silicon carbide diode after cutting to obtain the basic structure and material composition of the silicon carbide diode.

3. The method of claim 1, further comprising, prior to performing simulation in Geant 4:

in Geant4, the magnitude of the bias electric field, the incident direction of the incident particle, the type of the incident particle, and the energy of the incident particle are set.

4. The method of claim 1, wherein injecting incident particles into the silicon carbide diode comprises:

incident particles are perpendicularly incident from the surface of the positive electrode of the silicon carbide diode.

5. The method of claim 1,

the incident particles are high-energy fast heavy ions.

6. The method of claim 5,

the energy of the high-energy fast heavy ions is more than 200 MeV.

Technical Field

The invention relates to the technical field of radiation-resistant analysis of semiconductor devices, in particular to a damage analysis method of a heavy ion radiation silicon carbide diode under a bias electric field.

Background

In order to build efficient and highly reliable power systems, efforts have been made to improve power switching devices, and silicon-based diodes have been the main material of power switching devices. However, silicon-based diodes have poor heat dissipation and are limited in high power applications, and in addition, the performance of silicon materials has been close to the intrinsic characteristic limit of silicon materials through continuous research on silicon-based devices for many years.

The silicon carbide is a wide bandgap semiconductor material, the bandgap width of the silicon carbide is about three times of that of the silicon material, and meanwhile, the silicon carbide material has higher thermal conductivity, so that the silicon carbide-based device has good heat dissipation performance. At present, silicon carbide-based devices are mainly applied to high-power systems, which requires that silicon carbide also has good physical and chemical properties in high-voltage and high-current environments.

Therefore, the silicon carbide diode is widely used in power factor correction circuits and boost converters, and has the advantages of extremely low switching loss, high switching frequency, stable switching characteristics, high efficiency and the like. Meanwhile, the self thermal conductivity coefficient of the silicon carbide material is about 3 times that of the silicon material, so that the silicon carbide power device is expected to be applied to the space field to achieve the purposes of reducing the weight of electronic equipment, reducing loss, dissipating heat well and the like. When the silicon carbide device is applied in a space environment, the influence of various rays and particles in the environment on the reliability of the device is not negligible.

Although the flux of heavy ions in the space environment is low, the heavy ions have extremely strong energy loss characteristics, and the heavy ions incident into the silicon carbide diode can cause microscopic damage defects to device materials. These defects may severely affect the electrical performance of the device when the device is used in a high voltage, high current environment, and may even cause the device to fail.

Disclosure of Invention

Objects of the invention

The invention aims to provide a damage analysis method of a heavy ion radiation silicon carbide diode under a bias electric field, which utilizes Monte Carlo simulation software Geant4 and semiconductor device analysis software TCAD to carry out numerical simulation on latent track damage generated after the heavy ion radiation silicon carbide diode so as to analyze the influence of defect damage on the electrical performance of the device.

(II) technical scheme

In order to solve the above problem, according to an aspect of the present invention, there is provided a damage analysis method for a heavy ion radiation silicon carbide diode under a bias electric field, including: constructing a simulation model of the silicon carbide diode through Geant4 based on the basic structure and material composition of the silicon carbide diode; simulation was performed in Geant4, including: injecting incident particles into the silicon carbide diode, and simulating particle motion tracks of the incident particles in the silicon carbide diode under different bias electric fields and initial defect damage distribution of the silicon carbide diode; based on the simulation model and the initial defect damage distribution of the silicon carbide diode, the defect damage evolution process of the silicon carbide diode is simulated through TCAD software so as to analyze the influence of the defect damage on the electrical performance of the silicon carbide diode.

Further, before constructing the simulation model of the silicon carbide diode, the method further comprises: and utilizing FIB (Focused Ion beam) to longitudinally cut the silicon carbide diode, and calibrating the components of each layer of silicon carbide diode after cutting to obtain the basic structure and material composition of the silicon carbide diode.

Further, before performing simulation in Geant4, the method further includes: in Geant4, the magnitude of the bias electric field, the incident direction of the incident particle, the type of the incident particle, and the energy of the incident particle are set.

Further, injecting the incident particles into the silicon carbide diode includes: incident particles are perpendicularly incident from the surface of the positive electrode of the silicon carbide diode.

Further, the incident particles are high-energy fast heavy ions.

Further, the energy of the high-energy fast heavy ions is more than 200 MeV.

(III) advantageous effects

The technical scheme of the invention has the following beneficial technical effects:

the generation and evolution process of the latent track damage of the heavy ion radiation silicon carbide diode under different bias electric fields is observed and analyzed from two dimensions of materials to the device by using Monte Carlo simulation software Geant4 and semiconductor device analysis software TCAD, and the influence of the defect damage on the electrical performance of the silicon carbide diode is further simulated.

By changing the device model provided by the invention, evaluation research of heavy ion radiation experiments under different working states and working voltages can be carried out corresponding to silicon carbide diodes with different characteristic sizes or different growth modes. The radiation resistance of the device can be well predicted and evaluated while saving a great deal of time and expense.

The interaction relation between the bias electric field and the radiation damage is disclosed, a technical basis is provided for the radiation effect mechanism analysis and reliability evaluation of the silicon carbide device, and the method has important significance for promoting the application of the silicon carbide device in the aerospace field.

Drawings

FIG. 1 is a cross-sectional view of a silicon carbide JBS diode of an embodiment provided by the present invention;

FIG. 2 is a graph showing the trace distribution of Cu ions and secondary electrons when Cu ions are incident on a silicon carbide diode according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the variation of ionization energy loss with incident depth under different bias electric fields after Cu ions are incident on a silicon carbide diode according to an embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating the total energy deposition, energy deposition by Cu ions, and energy deposition by secondary electrons of Cu ions in a silicon carbide diode under different electric fields according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the distribution of space charge generated by Cu ion incidence in a silicon carbide diode according to an embodiment of the present invention;

fig. 6 is a schematic diagram of the evolution of transient current in a silicon carbide diode over time at different electric field strengths for an embodiment provided by the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

The present invention will be described in detail below with reference to the accompanying drawings and examples.

The invention provides a damage analysis method of a heavy ion radiation silicon carbide diode under a bias electric field, which comprises the following steps:

step S1: and utilizing FIB (Focused Ion beam) to longitudinally cut the silicon carbide diode, and calibrating the components of each layer of silicon carbide diode after cutting to obtain the basic structure and material composition of the silicon carbide diode.

Step S2: inputting the basic structure and material composition of the silicon carbide diode into Geant4 to construct a simulation model of the silicon carbide diode.

Step S3: the magnitude of the bias electric field, the incident direction of the incident particle, the type of the incident particle, and the energy of the incident particle are set in Geant 4.

Step S4: simulation is carried out in Geant4, incident particles are vertically incident from the surface of the anode of the silicon carbide diode, and the incident particles pass through anode metal and interact with the material of the silicon carbide diode, so that the particle motion trajectory of the incident particles in the silicon carbide diode under different applied electric fields and the initial defect damage distribution of the silicon carbide diode are obtained.

Step S5: based on a simulation model of the silicon carbide diode and initial defect damage distribution of the silicon carbide diode, defect damage evolution after the silicon carbide diode is simulated through TCAD software, and influence of the defect damage on electrical performance of the silicon carbide diode is analyzed.

Specifically, in the above steps, Geant4 (monte carlo package developed by the european nuclear Center (CERN) initiative) is software for experimental simulation of particles, and can simulate the transport of particles in the material in detail. Tcad (technology computer aid design) is a semiconductor process simulation and device simulation tool for determining the device structure of a material under a standard process, calculating electrical behavior based on the device structure, and extracting electrical parameters conforming to the standard from a device model.

When high voltage is applied to the silicon carbide diode, a high bias electric field can be formed inside the silicon carbide diode, heavy ion radiation damage of the silicon carbide diode under the bias electric field can be simulated by utilizing Geant4 software, and meanwhile, numerical simulation is carried out on latent track damage generated after incident particles irradiate the silicon carbide diode so as to analyze the influence of the bias electric field on the generation and distribution of the radiation damage.

The radiation damage is further converted into electron hole pairs, transient current caused in the silicon carbide diode by heavy ion radiation under different bias electric fields is obtained through TCAD, the influence of the bias electric fields on the heavy ion radiation damage of the silicon carbide diode is clarified from a micro mechanism to a macro effect, and the influence of heavy ion incidence under different bias electric fields on the electrical property of the silicon carbide diode is analyzed.

Wherein, the incident particles are high-energy fast heavy ions, and the energy of the high-energy fast heavy ions is more than 200 MeV.

Fast and heavy ions bombard silicon carbide diodes, i.e. when the target material is bombarded, energy is lost through inelastic collision of the ions with extra-nuclear electrons in the target material, and the energy loss mainly comes from incident particles and secondary electrons. The energy of deposition of fast and heavy ions along the incident path is localized to a small area, which may result in permanent structural changes, i.e., the creation of latent tracks, in a spatially limited area. The formation and morphology of the latent tracks depends not only on the type and energy of the incident particles, but also on the type of target material.

For conventional silicon semiconductor materials, about 3.6eV energy is required on average for each electron-hole pair to be generated, whereas silicon carbide materials require more energy to generate electron-hole pairs due to forbidden bandwidth. The electron hole pairs are generated in large quantity near the ion tracks, on one hand, the crystal lattices of the device materials are damaged, and on the other hand, the redundant electron hole pairs form transient current to influence the normal work of the device.

When voltage is applied to the device, a large bias electric field appears in the device, and the appearance of the electric field influences the movement of heavy ions, so that the size and the distribution of ionization energy loss are influenced.

The method for analyzing damage of the present invention will be described in detail below with reference to specific examples.